Electric generator



Jan. 12, 1960 E. L. SCHIAVONE 2,921,252

ELECTRIC GENERATOR piled May 2 1957 2 Sheets-Sheet 1 INVENTOR Mmwmm BYR3 @099 ATTORNEYS 1960 E. L. scHlAVoNE 2,921,252

ELECTRIC GENERATOR Filed May 28 1957 2 Sheets-Sheet 2 ACCUWLATOR ANDFILTER cmcun' CONDENSERS T T T A INVENTOR [lam/jam,

ATTORNEYS United States Patent @fiice 2,921,252 ELECTRIC GENERATOREdward L. Schiavone, Silver Spring, Application May 28, 1957, Serial No.662,223

2 Claims. (Cl. 322-2) This invention relates broadly to the electricpower generator arts and in its more specific aspects it relates toapparatus for translating mechanical motion into a constant voltage; andthe nature and objects of the invention will be readily recognized andunderstood by those skilled in the arts to which it relates in the lightof the following explanation and detailed description of theaccompanying drawings illustrating what I at present believe to bepreferred embodiments or mechanical expressions of my invention fromamong various other forms, arrangements, combinations and constructions,of which the invention is capable Within the spirit and scope thereof.

It is one of my primary purposes to provide mechanism providing uniformmechanical motion in a simple, economical and efiicient manner and totranslate such mechanical motion into usable electrical energy.

It is well known that usable energy in the form of an electric currentmay be generated by the distortion or vibration of certain crystals suchas barium titanate and similar piezoelectric crystals and that thefrequency of such current impulses depends upon the frequency of thevibrations to which the crystal is subjected. As far as I am aware noone has heretofore devised a highly efficient and commercially practicalapparatus using the principle of crystal distortion as a source ofcurrent which will automatically operate over long periods of time tofurnish a constant voltage.

It is therefore a purpose of my invention to provide a piezoelectricgenerator for furnishing operating voltage for a great many types ofelectrical devices, for instance my generator may supply operatingvoltage for hearing aids, life boat and the like transmitters andreceivers, ultrasonic generators, audio generators, walkie talkie units,portable radios and phonographs, alarm systems, photocell units,microphone preamplifiers, micro-wave communication, intercom units,signal generators, moisture meters, electric eye control for lens, musicboxes, smoke indicators, temperature indicators, Weather transmitters,and the like.

In evolving my generating apparatus I have eliminated the necessity forusing batteries and thus have banished from my apparatus the undesirablefeatures which are inherent in systems using chemical batteries, such asthe large voltage drop that occurs over a period of time and especiallytoward the end of the shelf-life of the battery. My invention alsoeliminates the danger of harmful radiations from batteries which aremade from radio-active materials. Many other highly advantageousfeatures flow from a power generating system which does not usebatteries, for instance my crystal generating apparatus may be used inhigh moisture and temperatures where batteries would have a short lifeand my generator may be used in applications where units must be storedunder operating conditions for long periods of time. Obviously undersuch stored non-use conditions batteries would rapidly deteriorate andwould not function properly when required to.

2,921,252 Fatented Jan. 12, 1960 While electric current has heretoforebeen generated by distorting or vibrating piezoelectric crystals suchdistortion has generally been accomplished by manual means and there hasbeen no prior concept of an organization by means of which a constantvoltage may be automatically furnished over long periods of time. It isthus an object of this invention to provide an apparatus whichincorporates mechanical means for causing uniform distortion of thecrystal to thereby produce a constant voltage. In accomplishing thisobject I have not sacrificed simplicity in the generating apparatus norhave I sacrificed economy of production of the apparatus or in theoperation thereof. In other words I have devised an apparatus involvingmechanical means, such as a resilient motor to cause a transducer tofunction to produce electrical impulses, which apparatus is economicalto produce and operate for long periods of time and is therefore morethan a device adapted merely for experimental laboratory work; insteadit is a commercially feasible apparatus of substantial utility for theproduction of voltage for the operation of many and varied types ofelectrical apparatus.

In attaining an apparatus endowed with the aforementioned and otherhighly desirable characteristics, I have, in certain forms which myinvention may take, used a spring motor as the prime mover and have usedescapement mechanism which is associated with the motor and a crystal ina manner to cause distortion of the crystal to produce voltage when themotor is operating. I have evolved a mounting and arrangement of thevarious components of the apparatus which is simple and results in ahighly efficient operation. For instance, I may use an elongated crystalor transducer element which is fixed at one end while the other end issubject to physical forces which cause distortion of the body of thecrystal to thereby cause generation of electrical impulses. The free endof the crystal may be operatively associated with the escapementmechanism for receiving therefrom distortive forces, or the free end ofthe crystal may be operative'ly associated with vibration generatingmeans whereby vibrations are transmitted to the crystal to thereby causethe generation of electrical impulses. It is within my contemplation toprovide various-arrangements for producing voltage by distortion of acrystal or by subjecting it to vibrations and in these variousarrangements, systems and organizations limited to use mechanicalmotorized means for generating the distortive or vibratory forces whichare applied to the crystal. In all such apparatus I provide for theapplication of uniform forces on the crystal to thereby produce aconstant voltage.

It is also within my contemplation to provide a generator which providesmechanical means for causing reciprocatory action by a coil within amagnetic field to thereby generate an electric current.

My invention also includes an accumulator and filter and 'voltagelimiting circuit for use with the voltage generating crystal or othervoltage generating means.

The electric generator of this invention is of a compact form which willproduce uninterrupted voltages for long periods of time while requiringlittle or no main tenance.

With the foregoing general objects, features and results in view, aswell as certain others which will be apparent from the followingexplanation, the invention consists in certain novel features in design,construction, mounting and combination of elements, as will be morefully and particularly referred to and specified hereinafter.

Referring to the accompanying drawings:

l is a fragmentary plan view illustrating the pre ferred form of myinvention more or less schematically.

Fig. 2 is a View taken on line 22 of Fig. 1.

Fig. 3 is a fragmentary plan view of a further form of my inventionillustrated more or less schematically.

Fig. 4 is a side elevational view of the generator illustrated in Fig.3. i

Fig. 5 is a fragmentary schematic view of a further form of myinvention. g

Fig. 6 is a fragmentary schematic view of a still further form of myinvention.

Fig. 7 is a fragmentary schematic view of another form of electricgenerator.

Fig. 8 illustrates an electric circuit which may be used with any of myelectric generators. i

In Figs. 1 and 2 of the accompanying drawings I have schematicallyillustrated the preferred form of my invention which comprises novel andunique means for applying distortive forces to a crystal in order togenerate electric impulses. I have used the numeral 1 to designate anelongated generally rectangular crystal transducer element which may bea barium titanate or other similar piezoelectric crystal having thenecessary properties to function as desired. The crystal 1 is fixedlymounted at one end in a socket 3 which is provided on a bracket 5 whichis fixed by screws 7 to any suitable supporting surface 9 which may be awall of a housing. The crystal 1 is preferably removably inserted in thesocket 3 to project upwardly therefrom and is fixed within the socketagainst any lateral movements relative thereto. Any suitable types ofelectrodes 11 may be fixedly applied to thecrystal in longitudinallyextending position therealong and an electric lead 13 is connected toeach conductor and to an accumulator and filter circuit which will behereinafter described. The electrodes 11 may comprise a flexibleconductive material conductively fixed to the crystal or it may comprisea conductive film which is sprayed on the crystal or any otherappropriate electrodes may be used.

I provide a resilient motor and escapement or actuatmg mechanism foroperative association with the other or free end of the crystal foruniformly applying distortive forces to said free end to thereby cause abending or distortion of the elongate body of the crystal. Such motorand actuating organization may embody a shaft 15 which is driven by aspring motor .which is not shown in connection with Figs. 1 and 2 but isillustrated in connection with the form of invention illustrated inFigs-3 and 4 of the drawings and will be described hereinafter. As theconventional spring motor is operating it will drive the shaft 15 at aconstant speed which may, of course, be predetermined, and the shaftdrives what I shall term an escape or actuating whee 17 which is fixedto the shaft for rotation therewith, the actuating wheel being driven'at the same predetermined constant speed. A continuous series ofactuating teeth 19 are formed about the periphery of the escape oractuating wheel, each tooth of the series of teeth being curvedbackwardly against the rotative path of the wheel as indicated by thearrow in Fig. 1 of the drawings.

Operatively mounted on the other or free end of the crystal 1 is a forceapplying member designated generally by the numeral 21 and which forms apart of the actuating mechanism. The force applying member 21 is .ofyoke-like rigid construction and is incorporated in the apparatusbetween the actuating wheel and the crystal for transmitting forces fromthe wheel to the crystal and converting said forces into distortiveforces within the crystal. The member 21 comprises a base providing asocket 23 which is mounted over the free end of the crystal. A stem 25projects from the socket and a pair of arms 27 divergingly extend fromthe stem 25, the arms being slightly curved inwardly toward each otherand an inwardly directed working pawl 29 being formed on the outer endof each arm. The force applying memher'21 is pivotally mounted as at 31,the pivot being suitably supported from any appropriate stationary pointwhich may be a wall of a housing. The force applying member ispreferably of integral construction and is pivotally mounted in positionso that the working pawls 29 will be in engagement with teeth 19 ofwheel 17 for a purpose which will become apparent as this descriptionproceeds.

As the actuating wheel is rotated by its shaft 15 which in turn iscaused to rotate at a uniform rate of speed by the motor the workingpawls 29 of the arms 27 will ride over the teeth 19, thus when oneworking pawl is riding over the crest of a tooth the other will be at alow point between teeth and as the wheel rotates the positions of theworking pawls relative to the teeth will change to thereby cause theforce applying member to pivot or rock on pivot 31 and since the end ofthe crystal or transducer is in inserted position in socket 23 thisrocking motion will be transmitted to thecrystal to distort or bend itin first one direction and then the other to thereby produce voltagewhich is carried off through the electrodes 11 and leads 13 to asuitable accumulator and filter circuit which will be describedhereinafter.

I have provided means for stopping operation of the apparatus when it isnot desired to generate electricity. One example of such means isdisclosed in Figs. 1 and 2 of the drawings and may consist of a pin orplunger 33 mounted on a wall 35 of a housing or in any other fixedsurface, the pin 33 being extended through the surface 35 forreciprocation therein and may be provided with an abutment head 37 onthe inner end thereof and an operating button or knob 39 on the otherend thereof. I wind a spring 41 about the plunger between button 39 andthe wall so that the spring constantly biases the plunger outwardly intoretracted or inoperative position. A radially projecting locking pin 43is fixed in the plunger and when the plunger is pushed inwardlyintooperative position locking pin 43 extends into a slot 45 which isprovided through wall 35 whereupon a slight .rotary action on button 39will move the pin 43 into the position behind surface 35 as illustratedin Fig. 2 of the drawings to hold the plunger in projected operativeposition. When it is in such position the head 37 will engage or abutthe adjacent arm 27 of the force applying member to thereby restrain itfrom rocking which will, of course, stop rotation of wheel -17 andconsequent unwinding or operation of the motor. To release the forceapplying member it is merely necessary to rotate the plunger untillocking pin 43 is aligned with slot 45 whereupon the plunger will beretracted under the action of spring 41.

In Figs. 3 and 4 of the drawings I have disclosed a modified form ofvoltage generator which, however, follows the same operating andgenerating principles as those involved in the apparatus describedabove. In this form of my invention I use the same type of crystal ortransducer and I mount it in the same manner as described above and Ihave also used the same reference numerals to designate similar parts.

The force applying member designated generally by numeral 47 comprises asocket forming base 49 into which the other or free end of the crystalis inserted. A neck or stem 51 extends from the socket 49 and a pair ofdiverging arms 53 extend from the stem. A pair of controlling arms 55project in parallel relationship from the ends of the arms 53, thus, theforce applying member forms a yoke-like structure. I provide a springwound motor 57 having a. Window key 59 whereby the motor may beactivated when the spring has unwound or run down through operation ofthe apparatus. A shaft 61 extends from the motor and is driven thereby.On the outer end of the shaft I eccentrically mount a disc 63 having aball bearing assembly 65 provided about the periphery of the disc.Consideration of the drawings indicates that the assembly is such thatthe disc and its ball bearing ring are positioned between-and inengagement with the arms 55 of the force applying member so that uponoperation of motor 57 and rotation of shaft 61 the eccentric mechanismincluding the disc and bearing ring will rock member 47 and consequentlythe crystal or transducer 1 will be bent or distorted from side to sideto thereby generate voltage as described. It is to be understood thatthe same means may be used for stopping operation of the apparatus ashas been described in connection with Figs. 1 and 2. It will also beunderstood that it is my intention to drive shaft 15 (Fig. 1) bya springmotor such as the motor 57 (Fig. 4).

In Fig. 5 of the drawings I have illustrated a further mechanism wherebyvibrators or distorting forces may be applied to a crystal. In this formof my invention, as in all the forms illustrated herein, I use a springor the like motor which mechanically initiates the vibrating ordistorting action. I provide a shaft 67 which is driven at a uniformrate by a motor such as motor 57 (Fig. 4) and fixed on this shaft is anactuating or kicker wheel 69 having a series of uniformly spacedprojections 71 about the periphery thereof. Pivotally mounted as at 73to any suitable support is an angled knocker arm 75 having a forwardknocker head 77 and a tail wheel 79 in position to be engaged and kickedby successive projections 71 as Wheel 69 rotates. I provide a springmember 81 which biases the arm 75 on its pivot so that knocker head 77is normally in raised position. I provide a tuning fork 83 which isfixed in position by any suitable means 85 so that one arm 87 is inposition to be tapped by head 77 when the apparatus is in operation. Asolid vibration transmitting element 89 extends from the end of theother arm 91 of the tuning fork, the element 89 being not only fixed toarm 91 but also in engagement with a crystal 93 which is mounted in anysuitable fixed socket 95.

It will now be recognized that when wheel 69 is caused to rotate eachprojection 71 will engage wheel 79 of knocker arm and pivot it to causethe arm 87 of the tuning fork to be tapped by head 77 thereby setting upvibrations which are carried to the crystal or transducer throughtransmitting element 89 to cause distortion in the crystal and thegeneration of voltage. The duration of the vibrations in the tuning forkwill be relatively long hence the striking intervals may not be asfrequent as though the head 77 was directly striking the crystal itself.

Fig. 6 is illustrative of a further arrangement which may be used forapplying distortive forces to a transducer such as a crystal. In certaininstallations it may be of advantage to use a ceramic disc type crystalor transducer 97 on each side of which is fixed an electrode 99 each ofwhich has a lead 100 connected to an electric circuit. Metal covers 101may be fixed to each electrode. I provide motor driven means forapplying distortive forces or vibrations to the transducer 97, suchmeans comprising a shaft 103 which may conveniently be driven by aspring motor 57 (Fig. 4). A kicker wheel 105 is fixed on the shaft andis provided on its periphery with a series of uniformly spacedprojections 107. I pivotally mount a knocker arm 109 as at 111, the tail113 being engageable with projections 107 and on the other end of thearm I provide a knocker head 115 and a spring element 117 biases thehead into position away from the crystal assembly. Thus, when wheel 105rotates the head 115 will intermittently knock against the crystalassembly to produce in the crystal the desired voltage.

Fig. 7 of the drawings illustrates another form of electric generator inwhich I again utilize a spring motor for initiating the voltagegenerating action. I have schematically disclosed a frame 119 acrosswhich is stretched any suitable type of diaphragm 121 formed of anysuitable material. Fixed to and extending rear wardly from the center ofthe diaphragm is a short tubular element 123 about which I form a coil125 of copper or the like wire from the ends of which leads 127 extendand are connected to a step-up transformer 129 which in turn isconnected to an accumulator and filter circuit 131. The apparatus alsoincludes permanent magnet members 129, 131 and 133 and the tubularelement 123 telescopically receives the free end of member 129. Themagnet members may be formed of a highly magnetized alloy which providesan intense magnetic field around the free end N of members 129, 131 and133 and the tubular element 123 telescopically receives the free end ofmember 129. The magnet members may be formed of a highly magnetizedalloy which provides an intense magnetic field around the free end N ofmember 129. Thus when tubular element 123 is caused by diaphragmvibrations to move in this field a pulsating DC. current will begenerated in the coil 125. In order to vibrate the diaphragm I provide atapping mechanism which may be the same as that illustrated in Fig. 6 ofthe drawings and is powered by a spring motor. I have used the samereference numerals to designate elements in Fig. 7 which are the same asthose shown in Fig. 6.

In Fig. 8 of the drawings I have illustrated an example of an electriccircuit which may be used with any of the generators which I havedescribed above. The circuit includes any suitable voltage generatingmeans 135 which is connected by leads 137 to a bridge rectifier 139, aconductor 141 is connected to the positive side of the bridge rectifierand to a pair of choke coils 143 which in turn are connected to avoltage limiting resistor 145 and the positive terminal 147 of thecircuit. A lead 149 connects the negative side of the bridge rectifier139 to the other terminal 151 of the circuit, thus making the voltageusable in a large variety of electrical devices.

It will now be appreciated that I have evolved electric generatingapparatus which is simple and efficient and will operate over longperiods of time to produce a constant voltage.

I claim:

1. Apparatus for translating mechanical motion into a constant voltage,including a piezoelectric crystal element and an escapement mechanism,means operatively connected to said escapement mechanism and fixed tosaid piezoelectric crystal element to apply distortive forces theretofor the generation of voltage thereby, and a resilient motor foroperating said escapement mechanism at a uniform rate and meansengageable with said escapement mechanism to stop the operation thereof.

2. Apparatus for translating mechanical motion into a constant voltage,including in combination, a piezoelectric crystal element productive ofvoltage when subjected to distortive forces, said piezoelectric crystalele ment being fixed at one end to a supporting surface and the otherend thereof being free, and an escape wheel having actuating teeth aboutthe periphery thereof and means for rotating said escape wheel at aconstant speed, a pivotally mounted force applying member connected tothe free end of said piezoelectric crystal element and having armsdiverging therefrom and in engagement with said actuating teeth onopposite sides of the axis of rotation of said escape wheel to causesaid force applying member to rock up on rotation of said escape wheelto thereby distort said crystal.

References Cited in the file of this patent UNITED STATES PATENTS405,471 Gleeson June 18, 1889 1,900,038 Bower Mar. 7, 1933 2,037,165Harrison et al Apr. 14, 1936 2,311,416 Salb et a1. Feb. 16, 19432,659,829 Baerwald Nov. 17, 1953 2,676,273 Oestreicher Apr. 20, 19542,691,159 Heibel Oct. 5, 1954 2,856,564 Derwin Oct. 14, 1958

